In general, a tape measure assisting apparatus for drawing an arc includes a fixing member, which presses and fixes a tape of a tape measure and is fixed to a center of a circle or a arc, and a writing instrument fixing part capable of fixing the writing instrument, and a tape measure integrally including such a tape measure assisting apparatus for drawing an arc.
In general, a tape measure is a measure having a long belt-shape, which is formed by engraving graduations on a thin cloth, metal, etc. Measures made from cloth, synthetic fiber, reinforce glass fiber, etc. are typically used for measuring a comparative long distance, and measures made from metal such as stainless steel are used for measuring a distance within 10 m in constructing buildings, etc.
Particularly, measures used in constructing buildings can measure a distance within a range of 2˜10 m. In such measures, graduations are displayed in various dimensions such as the dimension of inch or feet as well as in the dimension of cm or m.
Meanwhile, under constructing buildings or interiors thereof, or under wood processing works, it often occurs to measure a distance and to draw a circle or an arc. However, a conventional tape measure is easily used for measuring a distance, but is not suitable for drawing a circle or arc having a predetermined diameter.
Meanwhile, in order to improve such a conventional problem, such a scheme for including an arc-drawing-assisting apparatus in a tape measure or a scheme for integrally including such an assisting apparatus in a case of a tape measure has been suggested.
FIG. 1 is a view illustrating a conventional arc-drawing-assisting apparatus and a tape measure including the assisting apparatus.
As shown, the conventional arc-drawing-assisting apparatus and the tape measure including the assisting apparatus include a tape measure 110, which includes a case 116 receiving a tape 112 having graduations displayed thereon and a fixing lock disposed at an end of the tape measure so as to be locked to an object to be measured, and arc-drawing-assisting apparatus 120, which includes an upper case 130, which is included in an upper portion of the tape 112 and has a screw receiving part 132 formed at an upper side of the upper case 130 and a graduation checking plate 134, a fixing screw 140 assembled with the screw receiving part 132 formed on the upper case 130, a pressing plate 150 pressing the tape 112 through fastening of the fixing screw 140, a fixing needle 162 fixing a center of a circle or an arc, and a lower case 160 included at a lower portion of the tape 112 so as to be assembled with the upper case 130.
Particularly, the upper case 130 and the lower case 160 of the arc-drawing-assisting apparatus 120 have assembling protuberances 136 and protuberance receiving parts 164, respectively. Therefore, the upper case 130 and the lower case 160 are assembled with each other in such a manner that each assembling protuberance 136 is received in each corresponding protuberance receiving part 164 and each tightening screw 170 is assembled between them. Also, the pressing plate 150, which presses the tape 112 so as to prevent the center of a circle or an arc from being changed when the arc-drawing-assisting apparatus 120 draws the circle or the arc, is disposed between the upper case 130 and the lower case 160. The fixing screw 140 pressing the pressing plate 150 is assembled with the screw receiving part 132 of the upper case 130.
However, the conventional arc-drawing assisting apparatus and the tape measure including the assisting apparatus can not draw a circle or an arc in an accurate dimension or an arc at each angle, and has a structure assembled by a plurality of screws so that assembling force can be lessened when the screws are missed, thereby remarkably lowering efficiency in operation.